CVE-2026-75588 json
Mattermost Desktop App plugin popout scheme validation bypass
published 2026-09-17 52 d ago modified 2026-10-13 26 d ago also EUVD-2026-81678
- cvss
- 2.6
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 13%
- public exploits
- 0
- none known
Summary
Mattermost Desktop App versions <=6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme. Mattermost Advisory ID: MMSA-2026-00717
Patch / fix
- Mattermost Mattermost 6.2.3.0, 6.3.0
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 52 d ago
Exploit prediction
0.22% chance of exploitation in the next 30 days, higher than 13% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 2.6 | CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N |
Affected products
- Mattermost Mattermost
Classification
- Weakness
-
- CWE-1287 Improper Validation of Specified Type of Input
References
-
mattermost.com
/security-updates
vendor-advisory
Sources
- CVE List CVE-2026-75588
- NVD CVE-2026-75588
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.